OK, here is my 2 cents...
I lived in San Diego for about a year. I took a class at a university and we went out on a field trip to look at fualts. There is apparantely a huge fault line going up the 5, and I have heard it is about 50 years overdue. Never felt a quake there though.
Even further back, I spent about 5 months traveling around the bay area down to Monterrey. I won't forget the quake I encountered, a very freaky experience...
I was in my Toy 4 Runner and sitting at a stop light not far from the city of Santa Cruz. Suddenly my car started to shake...sort of a heavy vibration. I immediately thought, "oh my f***ing engine is done". I scrambled to turn off the car. It just kept shaking. I sat there for a moment in bewilderment, then the vibration stopped as quickly as it had begun. I looked forward at the intersection, and saw the traffic light swaying back and forth. That is when I realized I had just experienced a minor earthquake.
Obviously, this experience did not discourage me from living in San Diego, but once I left CA I knew I wouldn't move back. This is for other reasons. I really enjoyed my stay, but it was just too crowded and expensive. I still love to visit though. EDIT: Last visit was Phish Festival 8 in Indio...WOOHOO!!!
I would recommend looking into some of the southwestern states as well. Colorado has pretty mild winters overall (much milder than MN where I grew up), but the occasional huge storm (which I find sort of fun, like a snow day back in grade school). There is lots of sunshine here, and lots to do if you are into the outdoors. The city is the perfect size for me...big enough to have all of the amenities for a single guy, and small enough that it doesn't seem too crowded or overwhelming. I love it here.
EDIT: Almost forgot to mention we have Red Rocks ampitheater...if you are a concert goer this is MAJOR!
Other cool states I frequent in the southwest are Arizona and New Mexico. Arizona is a great state but I don't recommend Phoenix unless you want that big city thing. Albuquerque and Santa Fe are fun little cities, but I wouldn't live there, just a bit too isolated for me. If you don't want a city to live in, there are infinate options in this region...and it has the weather you are looking for.
Hope this helps!